Almost all drink makers caution against it, but one says it’s safe as long as you follow some special rules.

Japan’s vending machines are amazing all year long, but they’re especially awesome right now. That’s because every fall, like the leaves changing color, vending machines across Japan undergo a wonderful transformation and start dispensing hot drinks.

Throwing a few coins into a machine and getting a piping hot bottle of green tea, coffee, or cocoa is one of life’s little but great joys, and definitely something you’ll want to do as often as possible while you’re out and about in Japan. But sometimes there’s so much to see and do that you might not finish off your beverage before it gets cold, which raises the question: is it OK to pop Japanese drink bottles in the microwave to warm them back up again?

Ordinarily, we’d find out by just tossing a bunch of bottles into the microwave, cranking the power to the max, and counting up how many yen in damage we did to the office and/or how many employees suffered grievous injuries. For a change of pace, though, we decided to seek knowledge in a way that doesn’t require the blood sacrifice of personal health or company property. Instead, we checked the websites of several of Japan’s leading beverage companies to see what they said, and it turns out that almost all of them strongly caution against reheating a plastic bottle in the microwave.

● Coca-Cola: “Absolutely do not heat the bottle in a microwave.”
● Suntory: “The bottle may rupture, or the liquid content erupt, if the bottle is heated in a microwave. Both are dangerous, so please do not heat he bottle.”
● Kirin: “Please refrain from heating the bottle in a microwave. The container could rupture and/or the cap could fly dangerously off.”
● Pokka-Sapporo: “Do not heat the bottle in a microwave.”

However, we did find one company that said sure, go ahead and pop that bottle in the microwave, as long as you follow some special rules. That company is Ito En, makers of the popular Oi Ocha line of teas.

▼ A bottle of Oi Ocha (お～いお茶 in Japanese)

Some, but not all, of Ito En’s bottles are microwave safe. They usually have orange or gold-colored caps, but to be extra sure, you’ll want to look for a notification on the label that says “電子レンジOK,” meaning “microwave OK.”

▼ The notice, circled in blue

There are also a few other precautions Ito En asks you to take. First, you have to remove the cap. Failing to do so could cause excessive pressure to build up inside the container, causing it to burst.

Second, you can’t put a completely full bottle in the microwave. The bottle pictured here ordinarily holds 500 milliliters (16.9 ounces) of tea, but Ito En says it should only be microwave-heated if there’re 400 milliliters or less remaining. To help you check, there’s a handy clear section of the label, marked at 400, 300, 200, and 100 milliliters.

The amount of time it’s OK to heat depends on how much is left, with each liquid amount accompanied by a corresponding number of minutes (分 in Japanese) and seconds (秒). For this bottle, for example, 400 milliliters should be heated for 1 minute and 50 seconds for a 600-watt microwave, or two minutes for a 500-watt one. Ito En also cautions that these times are for tea that’s no hotter than lukewarm, so you’ll need to cut them down if your drink is already sort-of-level hot.

Sure enough, heating the bottle for the recommended time made its contents nice and hot, like a freshly brewed batch poured straight from the teapot.

Finally, Ito En says that each bottle of tea should be reheated in the microwave one time only, since the container isn’t designed for the stress of a large number of bouts of heating and cooling.

Sources: Ito En, Coca-Cola, Suntory, Kirin, Pokka-Sapporo
Photos ©SoraNews24
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